Currently, the electric vehicles (EV) and the plug-in hybrid vehicles (PHEV) are widely marketed as vehicles, which are navigable by electric power and are chargeable directly by the electric power from an outside-of-vehicle power system (i.e., directly by the electric power from a power outlet in a house). In those vehicles, an amount of charge/storage of the electric power to a storage battery in the vehicle is ever increasing due to a higher storage capacity of the storage battery, thereby a decrease of the charge time for charging the storage battery is an important issue. For a quick charge of the storage battery by the electric power from the outside-of-vehicle power system in response to a request from the vehicle, it is desirable to maximize the amount of supply of the electric power from the outside-of-vehicle power system, or a supply power amount, closer to the limit capacity of a breaker of the outside-of-vehicle power system, for quickly/speedily filling/charging the storage battery. In terms of such power supply technique, a patent document, Japanese Patent Laid-Open No. 2010-166768 (patent document 1) proposes, for example, a variable charge amount control/adjustment technique that adjusts a charge amount for a secure charging operation (i.e., for avoiding a breaker operation), when a breaker operation of interrupting a supply of the electric power is predicted.
For example, when a Home Energy Management System (HEMS) or the like is used as a high level device (i.e., a management device) for an energy management of an in-house power system that is installed in a house or the like, such a high level device is typically used for the charge amount control/adjustment of a charger disclosed in the patent document 1. In such control/adjustment, the charger exchanges information about the supply of the electric power with the vehicle, and the information from the vehicle is transmitted to the high level device. The high level device then calculates an instruction value of the charge amount for controlling the charger, based on an adjustment on how to distribute the electric power among each of the loads (i.e., electric appliances) in the in-house power system, so that the breaker of the in-house power system is not going to the operate (i.e., is not going to interrupt the supply of the electric power from the vehicle during the charge of the vehicle battery). The charger then charges the storage battery in the vehicle according to the instruction value from the high level device.
However, the high level device, such as HEMS or the like, may be implemented in various forms (i.e., either as an in-house installed type or a portable type). That is, the high level device may be a personal computer or a smart phone, which may not output an instruction on regular basis. Further, in case of device failure of the high level device, for example, the charger may have to operate independently (i.e., without receiving an instruction from the high level device). Even in such a situation, the power supply between the power storage device in the vehicle and the outside-of-vehicle power system is preferably performed without interruption (i.e., without causing an operation of the breaker to interrupt the power supply between the power storage device and the outside-of-vehicle power system.